Explosive



l 1 A U T Patented Aug. 23, 1932 w A. HAMMOND,OF ALBANY, onninonnrmnssrenoia :0 CALIFORNIA oar COM- No Drawing.

"PANY, OFHOAKLA'IND, oALIroRniA, a CORPORATION or CALIFORNIA This invention relates to explosives,- and particularly ,to a treatmentof blackpowder, and i has for its objects a process whereby the powder is rendered slow :bu'rni'ng while at-the same time retaining its-granular and free pouring characteristics so that Y it :may be handled inyconventional apparatus for fillingfuses; 1 i

Other objects of the in "ention will appear in the following description. r It has long been desirable to slowdown the burningspeedjof various powders used for fusemaking so as to get the required delay without an extremely long fuse which is objectionable for several reasons besides greatly increasing the danger of failure, and many prior attempts have been made to treat fuse powders both for slowing their burning speeds as well as to partially water proof them, or prevent spontaneous or slow decomposition. Such prior treatments have included admixing various slower burning powders or retarding substances with the fuse powder, also incorporating therewith oils, greases, parafline etc. to form a mass more or less moisture proof and of slower burning properties than theplain powder.

a It has also been found that various gums,

,'resins and pitches including asphaltum could be mixed as a dry powder, or melted into the powder or with the sulphur content powdered and admixed. Also various varnishes have been incorporated in blackpowder and other fuse powders in an attempt to control the explosive or burning properties thereof.

However, while these earlier methods all effected certain improvements in the properties of the powders, the requirements of i'their day were not at all the requirements of todaywhen successive delayfuses are an article of automatic manufacture and must be absolutely relied upon to set off a series of blasts in the order of the fuse numbers or delay indicia, and to do this every time under every condition of use.

Also since there is a tendency of the art to move toward the adoption of an all metal delay fuse of much shorter length than the old type fuses, and wherein the powder, of

definite quantity, is compacted under definite pressure in the bores of metal fuse tubes, it becomes a matter of vital importance that the time control and absolute homogeneity of the powder used be at constant. This is especially true with all metal delay'fuses as shown and described in my copending ,patent for blasting caps filed under Serial No. 438,304 on March 24,1930, for in the manufacture ofsuch fuses the powder must be absolutely uniform in its properties from end to end of the bore, and should ,also be free running for proper handling in the filling and compacting ap paratus.

, With the above requirements in mind it will be seen that a powder treated with a sticky varnish could not be handled, and if permitted to dry and then broken up would present irregularly agglutinated grains, also of uneven burning properties on. account of the settling of the varnish to the lower strata of themass; Several of the dry mixes were found fairly good but much too rapid in burning speed or too. erratic if more inert material wereadded.

Afterlongexperimentation I have found the proper, substance and the proper mode of treating black powder or other fuse powders whereby a perfectly homogeneous evenly retarded, free pouring, dampproofed and absolutely dependable powder for metalfuses may be produced, and a great many actual tests of metal delay fuses made with the powder,extending over a period of time, have notshown a single failure.

To prepare a fuse powder in accordance with my process I take a quantity of any fuse powder suchas black'powder, saturate itwithasolutionof a certain grade of asphaltum carried in a highly volatile solvent, andat once trituratethe mass until the solvent has evaporated toleave the powder granules dry and each coated on all sides with the asphaltum. Thegrade of asphal tum is one which will be free from stickin'ess, and the solvent should be one which will not act'to dissolve out thesulphur content of the'powder or else highly volatile so thatit may be gotten rid of before any ob all times absolutely III . solution. This will be found to 'jecti'o'nal action on the sulphur has taken place. V 7

As an example I prepare a solution in the proportion of asphaltum '40 grams to 250 c. c. of carbon bisulphide. The grade of asphal-' tum having a penetration test of Q to and preferably what is known as air blown.

I next add to a weighedquantity of black powder, placed in a '6 ounces, 80 c. c. of'the above asplialtum" rounded or enclosed in a film of the hard asphaltum, Tho if the pr'ocess has' notbeen' perfectly carried out or any slight agglutie nation should manifest itself the powder may be passed through a suitable screen to insure absolute uniformity and separate anyon desirable large grains.

Instead of the solvent above mentioned I i have also secured good results with carbon tetra-chloride,

also be'n'Zol'e, and I have used other grades of asphalt both softer and harder including gilsonite but lhave found the grade and solvent mentioned satisfactory in every respect. p H l i v 3 Theabove' treatmentyields a powder-which wheneonfined in a metal fuse willburn at about one foot in 144 seconds, tho for still slower burning it suffices to" increase, the" density of the asphaltic solution.

By theabove process of using adefini't'e' quantity of a known density of asphaltum solution on a unit quantity of powder and triturating same untildry and said definite quantity of as'phaltum hasevenlyfcoatedthe grains of the unit quantity of powder it is" possible to obtain a uniform product without.

variance, as, required for modern delay fuse production, and'which I believerepresents a V valuable and new step forward the art.v

I therefore claim: H;

I. Themethod oftreatingybla'ck powder which comprises mixingthe powder with a solution of asphaltum cfarrled 1111 a volat le.

withthe asphaltum. Y v I 2. The metl od of treating blackpowder.

which comprises mixing the powder with a solution'of hard aspha'ltum dissolved in car:

'bon bisul'phide and tritur'ating the mass until l a substantially dry powder results.

suitable receptacle, say f sate f treatedwill be found to 7 which comprises mixing the powder with a Y solution of asphaltum of from O to 10 penetration dissolved in carbon bisulphide and trituratingthe mass until a substantially dry powder results. I

The Inethodof treating blacklpowder which comprises mixing the powder with a solution of hard asphaltum dissolved in carbon bisulphi-de and ,t'riturating the mass until a'sub'stantially dry powder results, carrying on the exterior of its granules about eight per centum of asphaltum'by weightto the weight of'untreated powder; 1 7 7 V V 5 An explosive comprising black powder, the inuividual-grains of which carry an en-' veloping' coat of 7 hard asphaltum HOD-adv hesi ve at ordinary temperatures, whereby the powder is free flowing.

'6. An explosive COInpI lS Hfl'g blaCk powder,

the indiv'dual grains of'which carry an enveloping coat of hard asphaltumnon-ad' hesive at ordinary temperaturesyand -in quantity'equal to about 8% fofthe weight of the untreated powder, whereby the powder is free flowing. a r

" JOHN A. HAMMOND. V 

